Method of filling pits



O. SITERN .METHOD OF FILLING PITS Filed July 5, 1929 OQO Patented Feb. 2a, 1932 UNITED STATES oTToKAR STERN, onfvrIENNALfAusTRmff aff METHOD oF ni'riiiiiGI-TITHS .f; t l" Application med July 5, 1929, serial-,Na

nalgas-iteBearer iiiajauiag Amaieriai: at :theage-nager manning-tube;irheoracna This invention relates to an improved method of filling pits Lwith an increased -effect of compression by which tubular driving piles are sunk into the ground by ramming, f

@01eme ferme@ :by

v5 boring or flushing and by means of an inner tubing of the same the filling material is introduced into the pit during the withdrawal of the driving piles. Y j

According to the present invention the tube 1,0 for the introduction of the filling material t (the filling tube) is of considerably smaller Vdiameter than the driving-tube. Thusfthe filling material emerges from the said tube with a head which isa multiple of the speedl at which the tubing is hoisted out of the soil.

This follows from the law of hydraulics. concerning thevinverse proportion ofV heads and sectional areas.

If, for instance, the tubing and consequently the pile driven by it has a sectional area of 2200 sq. cm., while the `filling tube has a sectional area of 280 sq. cm. only, their proportion is 1 :78. V1f, now, the tubing is hoisted up atl a' speed of 0.5 metre per second, the fillingmaterial-pours out at a speed kof 0.5 l 4:4 m./sec., which corresponds to a momen-V tum of about 0.8 kgm. for each kg. of the fill` ing material. Thus, if a5 m. (about 17 ft.) concrete column within the filling tube of the Y 30 above diameter weighs about 2500 kg., this whole mass is subjected to a compressioneffeet of 2000 kgm., which corresponds to a driving action of more `than 400 blows of 5 kgm. each. This is equivalent to the process of pouring the concrete in cm. layers and tamping each layer Vwith. sixty heavy Vand powerful blows.

Of course owing to this ramming effect, the wall of the pit is subjected to a displacing pressure, which more or less enlarges itssec- Vtional area depending on the nature of the soil.

Experience has also shown that piles made according to the present invention take `10% to moreconcrete than corresponds toA the cubature of the pit, which naturally results in an increased carrying capacity.

The smaller (within practical limits) theV proportion between the sectional areas ofthe driving-tube and the lling-tube, the stronger this Jcould fbe increased 'ufp to the`A speed Vvof Y freejdrop'corresponding to:theh "eig'fh't` of the Y e':filling-mafieare e mangiate.

compression.`depndsjnot :only oni "the speed `square of the speed. Thus according to the example given above, with a filling-tube of half they sectional area, viz. 140 sq. om., the head of the Aiilling materiall would'be 8 m./sec.y and the venergy per 1 kg.=3.2 kgm'., i.V e. the quadruple. On theother hand, the speed at Which thetubing isy hoisted out of the ground Vincreases to the same extent the head of the filling material. A Y. further feature of the present invention thereforeconsists in hoist- V ing upthe tubing in short lifts and each time with ar sudden jerk, because greater speeds inthe hoisting of the tub-ing, at their sudden annihilation, cause a powerful pressure of the moving mass (the iilling material). Concrete vor any other mortar mixture, broken stones, sand, slag and the like may be used 8K5 as filling material. q One mode ofcarrying out the method ac-y cording Vto the present invention is shown o diagrammatically and by way of example in .t the drawing. Y W The driving pile 1, which has been sunk for instance by ramming, is providedV with a centrally disposed tubing 2' through which the filling material is introduced. The length 1,. ofl thetubing 2 can be suitably increasedby "95 .an extension tube 3. The said tubing 2 rests VVon a ca'sing'll, forming the deposition coin- .Y

partment and at the same time the bottom end of the driving pile'- The tubing is charged with lling material up to a height H accordo `ing to the desired eiect of compression, and subsequently the driving pile is withdrawn a certain distance.` The filling and withdraw- -ing operations are carried out` successively, v

5 or they may overlap one another.

I claims:-

o 1. The method of fillingpits which consists in sinking-a cylindrical smoothdriving pile, 1 introducing the filling material linto a filling f Y 10 tube passing through and being of considerl' "j able smaller diameter thanfsaiisdrivimgpiiegy; qu. v.; `V1 f hoisting the driving pile at intervalswith a sudden jerk in short liftsv and abruptiy Il l ping the hoisting motion each time iii/orderu Y 4the column of material within the'ziilling tube e finto enhancedfpressre ofthefllingl material 'ff f' thepitbelwftheldrixngpile; v Y V Y2, Thefmethodas'clai edf Vnglclaiin.1,fi1irl j column ofv'material Within the .llingtbe i i., 5 1 'im' -Yy-llg th-,effect ovicomprgssviou Y' v In tesltmony whereoflaiiixjmysignature. 

